Lead scavenger compositions



United States Patent 9 LEADSCAVENGER- COMPOSITIONS Venard- E. Yust, A-lton,,and'.lohn L. Bame, East Alton,

Ill., assignorsto", Shell Development Company, Emeryville, Califi, a corporation of Delaware No Drawing. Application June 27, 1952 Serial No., 296,096

This invention relates to compositions which are useful as scavengers with leadanti-kno'ck compounds.

The use of-1ead compounds in'gasolines to increase the octane ratings thereof is extremely widespread. There are, however, several rather serious adverse efiectswhich accompany the use of leaded gasolines; One of these effects, the deposition ofvarious lead compounds within the combustion chambers of the engines, has beenat least partially remedied by the use of halohydrocarbon scavengers such as ethylene dibromide. Another adverse effect, Whichhas been attributed to the lead anti-knock compounds, is mis-firing of the engine due to spark plug foul ing. This spark plug fouling is quite prevalent under conditions of high temperature engine operation and, particularly in the case of aircraft engines, is a very serious type oftrouble.

It is, therefore, an object. of the present invention to overcome the previous shortcomings arising from the use of leaded gasolinesi It is a further object to provide novel scavenger compositions for" use with lead antiknock compounds andingasoline fuels. Another object is to provide novel fuel compositions containing said scavenger compositions. Other objects will be apparent hereinafter.

It has now been found that the use, as alead scavenger in leaded gasoline fuel compositions, of a mixture of a halohydrocarbonscavenger and of a smaller amount of certain phosphorus compounds will result in greatly improved operation of spark ignition internalcombustion engines. More particularly, the use of such scavenger compositions substantially eliminates spark. plug fouling, or at least minimizes such fouling to a oint: Where it is no longer a material consideration in engine operation. This outstanding advantage is obtained without having the anti-knock characteristics of thefuel deleteriously affected by thepresence of thescavenger compositions.

The phosphorus compounds in the present: scavenger compositions will be referred to hereinafter asantirfoula ing compounds.

The halohydrocarbon scavenger which. makes up the major proportion ofi-thescavenger compositions of the present invention maybe; for, example, any-of the numerous halogen, scavenger compounds already known, such asethylene dibromide and-ethylene dichloride (U. S. 2,398,281), acetylene tetrabromide (U. S. 2,490,606), hexachloropropylene, monoand. polyhalo propanes, butanes and pentanes (U. S. 2,479,900 and, U. S. 2,479,902), polyhalo alkyl,benzenes (U. S. 2,479,901 and U. S. 2,479,903), and the like, l1a.ving a volatility between about 100 and about 0.1mm. Hgat50 C.

The phosphorus anti-fouling compounds of the present invention arelhose having the following formula:

organic. radical, at, least. oneQR. being-a, cyclic organic radical, x is an integer from 1 to '3', inclusive, y is an 2,328,195 Patented Mar. 25, 1958 2. integer from O to 1, inclusive, 2 is an integer from 0 to2, inclusive, and x+z=3.

A preferred group ofthe foregoing class of compounds, obtained when X is an oxygen atom, is made up of phosphonic andphosphonous acids and the mono and diesters thereof; phosphinic andphosphinous acids andtheir esters; and primary, secondary and tertiary phosphines and phosphine oxides. Of the above group, the neutral esters and tertiary phosphines and tertiary phosphine oxides are preferred. a

It will be noted that at least one of the Rs in the above formula mustbe a cyclic organic group. So long as this requirement is satisfied, the remaining Rs may be either hydrogen atoms or aliphatic organic groups; it ispreferred, however, that all of the Rs be organic groups. It is further preferred. that. all of the organic groups be cyclic.

stituted upon, the cyclic groups markedly increase the anti-fouling effectiveness, of the. present phosphorus compounds. radicals do not, in general, adversely affect the elficiency of the phosphorus compounds as anti-fouling agents, it is preferred that the R groups be unsubstituted hydrocarbyl radicals.

When using the scavenger compositions of the present invention, the total amount of halogen scavenger plus anti-fouling agent present will generally fall between about 0.6 and about 1.5 theories, based upon the lead content of thegasoline, but may; advantageously be as low-as 0.4 or as high as 2.0 in some cases. The preferred range is from about 0.9 to about 1.2 theories.

The ratio-of the twocomponentsof the scavenger composition is rather important; For example, if the proportion of, halogen scavenger present is too large, excessive-wear and corrosion of certain operating parts, such as exhaust valves and valve guides, is noted. If too small a quantity of halogen scavenger is used, the lead deposits are not effectively scavenged. if too small a quantity of the anti-fouling compound is used, the spark plug fouling will not be materially. reduced; and if too much of that compoundis-present the amountsof-depositsand the plug fouling are: both increased. In general, the theory ratio of the halogen scavenger or scavengers to the anti-fouling agents should be between. about 3:2 and about :1. Forbestresults this ratio should be between about 2:1 and about 15:1. Asan additional limitation, the total scavenger mixture and the ratioof components therein should be adjusted so that the anti-fouling compound is presentin an amount-of between about 0.01 and about 0.6-

theories, and preferably. between about 0.05 and about 0.4" theories; It is preferred that. the Weight concentration of the anti-fouling additive in the fuel be kept below 0.1%. Itisto be understood that more than one ofthe compounds from eachclass (i. e., halogen scavenger or anti-fouling agent), may be used in .any single composition,j,iust so-the-total quantity of eachtype-falls within theglirnitsxset forth above.-

Theterm theory, when used: in conjunction with a halogen scavenger compound, designates the amount of scavenger: required to react stoichiometricallywith a given amount -oflead anti-detonant so-that all of the lead'atoms and all of the halogen atoms formPbBr or PbGlg. In other wordsja theory of scavenger-is an amount-which While substituents other than hydrocarbon a contains two atomic proportions of halogen for each atomic proportion of lead in the anti-detonant, or, a theory of the halohydrocarbon scavenger is one mol of the halohydrocarbon scavenger divided by one-half the number of halogen atoms per molecule, for each gram atom of lead in the lead anti-detonant present, and therefore, the number of theories of halohydrocarbon scavenger present in a given composition is equal to the number of mols of halohydrocarbon scavenger present multiplied by one-half the number of halogen atoms per molecule, for each gram atom of lead in the lead anti-detonant present. As applied to the anti-fouling compound, the term theory designates the amount required to react stoichiometrically with the lead so that all of the lead atoms and all of the phosphorus atoms form Pb (PO Therefore a theory of the anti-fouling compound is one mol thereof multiplied by two-thirds (that is, two-thirds of a mol of the anti-fouling compound), for each gram atom of lead in the lead anti-detonant present, and therefore the number of theories of anti-fouling compound present in a given composition is equal to the number of mols of the anti-fouling compound present multiplied by three-halves, for each gram atom of lead in the lead anti-detonant present.

While it is to be understood that the present compositions may be utilized in any leaded gasoline fuel, the compositions are of particular importance with respect to use in reciprocating internal combustion engine gasoline fuels, and especially such aviation fuels. This is true because of the relatively more frequent occurrence of spark plug fouling in aviation engines, with the greater inherent danger to human life in the case of failures of such engines. In addition to the lead anti-detonant and the scavenger composition, the gasoline fuels, or the concentrates for addition thereto may also contain corrosion inhibitors and stabilizers, such as 2,4-dimethyl-6-tertiary butyl phenol and other alkyl phenols, N,N'-dibutyl pphenylene diamine, hydroquinone, phenyl-alpha-naphthylamine, N-butyl-p-aminophenol, alpha-naphthol, etc., dyes and the like.

By the term leaded gasoline, and the terms of similar import, is meant a petroleum fraction boiling in the gasoline hydrocarbon range (between about 50 F. and about 450 F.) to which has been added a small amount,

usually between about 1 and about 6 cc. per gallon, of Y fins, or the stability may result from the use of oxidation stabilizers, such as those mentioned above. A few of the phosphorus compound anti-fouling agents of the present invention are known to have slight oxidation inhibiting properties; these properties are so weak, however,

that it is much preferred that an additional oxidation inhibitor, i. e., a non-phosphorus stabilizer, be used in the present gasoline compositions.

As indicated above, the scavenger compositions of this invention are particularly useful in aviation gasoline. By the term aviation gasoline is meant a relatively high grade of gasoline fuel used in aviation engines, as distinguished from the lower quality gasolines, or motor fuels used in automotive engines. Aviation fuels have a more closely specified boiling range, generally running from a minimum of about 100 F. to a maximum of about 350 F. The octane number of such fuels is generally in excess of 100. Because of the demand for high quality, thermally cracked fractions are never used in aviation gasolines. Catalytically cracked fractious may sometimes be used, but only after treatment to remove olefins. One of the reasons for the restrictions upon incorporation of cracked gasolines in aviation fuels is that the oxidation stability of aviation fuels must be much greater than that required for motor fuels. For example, when tested according to a method such as described in the patent issued to Thomas W. Bartram, U. S. 2,256,187, an aviation fuel base stock will go well beyond 4 or hours before the oxygen pressure will have decreased by 5 pounds per square inch. 7

The following are examples of compositions suitable for use according to the present invention:

Example I:

Tetra-ethyl lead 1.0 theory ethylene dibromide 0.2 theories bis-(3,5-dimethylphenyl) 2,5-dimethylbenzene phosphonate Example II:

Tetra-ethyl lead 1.0 theory ethylene dibromide 0.1 theory phenyl dibenzenephosphonite Example III:

Tetra-ethyl lead 1.0 theory ethylene dibromide V 0.1 theory tri-(2,4-dimethylphenyl) phosphine Example IV:

Tetra-ethyl lead 1.0 theory acetylene tetrabromide 0.4 theory S,S-diethyl benzenedithiophosphonite Example V:

octane aviation gasoline containing, per gallon 0.5 cc. tetra-ethyl lead 1.0 theory ethylene dibromide 0.2 theory diphenyl benzenephosphonate 0.02 gr. 2,4-dimethyl-6-tert.-butylphenol 7, Example VI:

Aviation alkylate containing, per gallon 4.6 cc. tetra-ethyl lead 1.0 theory ethylenedibromide p I 0.04 gr. 2,4-dimethyl-6-tert.-butylphenol 0.1 theory tri-(p-xenyl) phosphine oxide Example I VII:

Tetra-ethyl lead 1.2 theories hexachloropropylene 0.2 theory diallyl benzenephosphonate Example VIII:

Tetra-ethyl lead 0.8 theory ethylene dibromide 0.2 theory dimethyl p-dimethylaminophenyl phosphine sulfide Example IX:

' Tetra-ethyl lead 1.5 theories hexachlorobutadiene-lfi, 0.1 theory di-(3,5-dimethylcyclohexyl) cyclohexanephosphonite Example X:

76 octane motor fuel containing, per gallon 2.1 cc. tetra-ethyl lead 1.0 theory ethylene bromide 0.5 theory ethylene dichloride 0.2 theory diphenyl benzenethionophosphonate 0.06 gr. N,N-dibutyl p-phenylene diarnine Example XI:

/130 grade aviation gasoline containing, per

gallon 4.6 cc. tetra-ethyl lead 1.0 theory ethylene dibromide 0.2 theory cyclopentadienyl dibenzenephosphinate 0.04 gr. 2,4-dimethyl-6-tert.-butylphenol Example )GI:

Tetra-ethyl lead I 0.5 theory ethylene dibromide 0.1 theory tri-(2,5-dimethylphenyl) phosphine oxicle adam:

iTet'r a ethyl lead t 0.8 ,theor 'jeth lenejdicliloi'ide I 0.2 theory 'diphe'nyl benzenephosphonite Example XIV:

Tetra-ethyl lead v 1.0 theory ethylene 'dibromide ":1 theory phen' l dibenzene hos n'inate Example XV: v p

Motor gasoline ontaining'per gallon 1.6 cc; tetraeth'yllea 1.0 theory hexachloi'oethane t 0.2 theory 'triphenylphosphine 0.06 gr. N-nut laminophenol Example XVI: v v

Tetra-ethyl lead V 1.0' theor ethylene dibrornide v 0.05 theory tri-(2,5-dir'nethylphenyl) -phosphiiae Example XVII:

"Tetra-ethyl lead 1.0 theory ethylene dibromide 0.5 theory di-(2-methyl-3-indolyl) Example XVIII:

Tetra-ethyl lead 0.8 theory'ethylenedibromide v p I 0.2 theory ethyl benzene(p-methylbenzene)phosphinite Example XIX:

Tetra ethyl lead 1.0 theory ethylene dichloride 0.1 theory tri-u-naphthyl'phosphine Example XX:

Tetra-ethyl lead 1.0 ethylene dibromide p 0.5 theory ethylene dichloride 0.5 theory di'octyl styrenephosphonate Example XXI:

Tetra-ethyl lead 1.0 theory ethylene dibromide 0.1 theory N-phenyl 'di-'(2,5-dirnethylbenzene) phosphinic amide Example XXII:

Tetra-ethyl lead 1.0 theory ethylene dibromide 0.1 theory tri-(2,4-dimethylphenyl) phosphine oxide Example XXIII:

Tetra-ethyl lead 1.0 theory ethylene dibromide 0.1 theory tri-(3,3,S-trimethylcyclohexyl) phosphine It is to be understood that the order of mixing the various constituents of the present compositions is immaterial. For example, the anti-fouling compound may be added to a gasoline which already contains the antiknock compound and halogen scavenger. Likewise, the metallo-organic anti-knock agent, the halogen scavenger and the anti-fouling compound may be first mixed, stored and handled as a concentrate, and added to the gasoline at a later time. A typical concentrate of this latter type has approximately the following composition:

Weight percent phosphinic acid Tetra-ethyl lead 55- Ethylene dibromide 25-30 Tricresyl phosphine -15 Kerosene, inhibitor, dye stabilizer, etc 3-6 Under other circumstances it may be desirable to mix the halogen scavenger and the anti-fouling agent, or the anti-knock agent and the anti-fouling agent, in the degust 17, 1951, now abandoned, which is in turn a continuation of our application Serial No. 167,376, filed June 10, 1950, now abandoned.

We claim as our invention:

1. A fuel composition for internal combustion engines consisting essentially of a stable gasoline, a minor efiective anti-detonant amount of a tetra lower alkyl lead anti-detonant, and a scavenger mixture for said anti-detonant consisting essentially of a halohydrocarbon scavenger and of a phosphorus compound having the formula:

wherein X is a chalcogen atom having an atomic number of from 8 to 16, inclusive; R is selected from the group consisting of hydrogen atoms and hydrocarbyl radicals, at leastone R being acarbo-cyclic radical; x is an integer from 1 to 3, inclusive; y is an integer from 0 to 1, inclusive; z is an integer from 0 to 2, inclusive; and x+z=3; said 'halohydrocarbon scavenger and said phosphorus compound being present in amounts such that where (a) is the number of mols of said halohydrocarbon scavenger present multiplied-byone-half the number of halogen atoms per molecule, for each gram atom of lead in the lead anti-detonant present, and (b) is the number of mols of said phosphorus compound present multiplied by three-halves, for each gram atom of lead anti-detonant presenL the total of (a) plus (b) is from about 0.4 to about 2.0, (b) is from about 0.01 to about 0.6, and the ratio of (a) to (b) is from about 3:2 to about :1.

wherein X is a chalcogen atom having an atomic number of from 8 to 16 inclusive; R is selected from the group consisting of hydrogen'atoms and hydrocarbyl radicals, at least one Rbe'ing a carbo-cyclic radical; x is an integer from 1 to 3, inclusive; y is an integer from 0 to 1, inclusive; z is an integer from 0 to 2, inclusive; and x+z=3; said halohydrocarbon scavenger and said phosphorus compound being present in amounts such that where (a) is the number of mols of said halohydrocarbon scavenger present multiplied by one-half the number of halogen atoms per molecule, for each gram atom of lead in the lead anti-detonant present, and (b) is the number of mols of said phosphorus compound present multiplied by three-halves, for each gram atom of lead anti-detonant present, the total of (a) plus (b) is from about 0.4 to about 2.0, (b) is from about 0.01 to about 0.6, and the ratio of (a) to (b) is from about 3 :2 to about 100:1.

3. A lead scavenging composition for use with a leaded anti-detonant gasoline fuel for internal combustion engines consisting essentially of a halohydrocarbon scavenger and of a phosphorus compound having the formula:

wherein X is a chalcogen atom having an atomic number of from 8 to 16, inclusive; R is selected from the group consisting of hydrogen atoms and hydrocarbyl radicals, at least one R being a carbo-cyclic radical; x is an integer from 1 to 3, inclusive; y is an integer from 0 to 1, inclusive; z is an integer from 0 to 2, inclusive; and x+z=3; said halohydrocarbon scavenger and said phosphorus compound being present in amounts such that where (a) is the number of mols of said halohydrocarbon scavenger present multiplied by one-half the number of halogen atoms per molecule, and (b) is the number of mols of said phosphorus compound present multiplied by three-halves, the ratio of (a) to (b) is from about 3:2 to about 100:1.

4. A composition in accordance with claim 1 in each R is a carbocyclic radical.

5. A composition in accordance with claim 1 in at least one R is an aryl radical.

6. A composition in accordance with claim 1 in each R is an aryl radical.

7. A composition in accordance with claim 1 in at least one R is an alicyclic radical.

8. A composition in accordance with claim 1 in each R is an alicyclic radical.

9. A composition in accordance with claim 1 in the phosphorus compound has the formula:

wherewherewherewherewherewherein X is a chalcogen atom having an atomic num ber of from 8 to 16, inclusive; R is a carbocyclic radical; and y is an integer from to 1, inclusive.

10. A composition in accordance with claim 1 wherein the stable gasoline. is a stabilized gasoline, the tetra lower alkyl lead anti-detonant is tetraethyl lead, the halohydrocarbon scavenger is a mixture of ethylene dibromide and ethylene dichloride, the phosphorus compound is bis(3,5-dimethylphenyl) 2,5-dimethylbenzenephosphonate, and (b) is from about 0.05 to about 0.4.

11. A composition in accordance with claim 1 wherein the tetra lower alkyl lead anti-detonant is tetraethyl lead, the halohydrocarbon scavenger is ethylene dibromide, the phosphorus compound is trixylenylphosphine oxide, and (b) is from about 0.05 to about 0.4.

12. A composition in accordance with claim 1 wherein the tetra lower alkyl lead anti-detonant is tetraethyl lead, the halohydrocarbon scavenger is ethylene dibromide, the phosphorus compound is tri-(2,5-dimethylphenyl)phosphine, and (b) is from about 0.05 to about 0.4.

13. A composition in accordance with claim 1 wherein the stable gasoline is a stabilized aviation gasoline boiling within the range 100 F. and 350 F., containing no thermally cracked gasoline fractions and no olewherefinic catalytically cracked gasoline fractions, the tetra lower alkyl lead anti-detonant is tetraethyl lead, the halohydrocarbon scavenger is ethylene dibromide, the phosphorus compound is tri (3,3,5 trimethylcyclohexy) phosphine, and (b) is from about 0.05 to about 0.4.

14. A composition in accordance with claim 1, wherein each R is a hydrocarbyl radical, (b) is from about 0.05 to about 0.4, and the weightconcentration of the phosphorus compound in the fuel is below 0.1%.

15. A composition in accordance with claim 6, wherein X is oxygen, (b) is at least about 0.05, and the ratio of (a) to (b) is up to about 15:1.

16. A composition in accordance with claim 14, wherein the bonding valence of each carbocyclic R is on a ring carbon atom.

17. A composition in accordance with claim 16, wherein the halohydrocarbon scavenger comprises ethylene dibromide, and X is oxygen.

18. A composition in accordance with claim 16, wherein the phosphorus compound has the formula:

ama.

wherein y is an integer from 0 to 1, inclusive.

19. A composition in accordance with claim 18, wherein X is oxygen, (11) is from about 0.05 to about 0.4, and the weight concentration of the phosphorus compound in the fuel is below 0.1%. V

20. A composition in accordance with claim 19, wherein the bonding valence of each carbocyclic R is on a ring carbon atom, and the halohydrocarbon scavenger comprises ethylene dibroinide.

References Cited in the file of this patent UNITED STATES PATENTS 2,265,819 Rosen Dec. 9, 1941 2,405,560 Campbell Aug. 13, 1946 FOREIGN PATENTS 600,191 Great Britain Apr. 2, 1948 

1. A FUEL COMPOSITION FOR INTERNAL COMBUSTION ENGINES CONSISTING ESSENTIALLY OF A STABLE GASOLINE, A MINOR EFFECTIVE ANTI-DETONANT AMOUNT OF A TETRA LOWER ALKYL LEAD ANTI-DETONANT, AND A SCAVENGER MIXTURE FOR SAID ANTI-DETONANT CONSISTING ESSENTIALLY OF HALOHYDROCARBON SCAVENGER AND OF A PHOSPHORUS COMPOUND HAVING THE FORMULA: 